Method of melting glass



Sept. 13, 1932.

F. J. BULASK 1,877,714

METHOD OF MELTING GLASS Filed Nov. 18, y1929 3`Sheets-Sheet l 4 l 'gn/vanto@ Sept. 13, 1932. F. J, BULASK Y 1,877,714

METHOD oF MELTING GLASS l Filed Nov. 18, 1929 5 Sheets-Sheet V2 n FrahcsJBu/as/i.

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3 Sheets-Sheet 3 F. J. BULASK METHOD oF MELTING GLASS Filed Nov.

sept. '13, 1932.

y 31a/vanto@ Francis Ju/a.

aucun/g5 ure l. Figure 3 is a horizontal section of the Patented Sept.. 1932 .rnANcI-s amiLasx, Ior 'oLnndomdfAssIGNon or ONE-'HALF To GEOBGETW. I,

'BATCHELL AND FRANZ G. SCHWALB, BOTH OF TOLEDO, OHIO y mnrrronfor MEL'rrNG Grass i Animation ma Novemberis, 1529. serial no. 407,960.

This invention relates to a'methrid of ,and

a paratus formelting glass and has for its .o ]ect to provide a method and apparatus whichwill simultaneously mix and melt glass materials. VMore particularly theobject of the invention is to expose material' added to thev furnace to intense heat promptly,"

a part of this specification,` Figure lis 'a' ver-v tical longitudinal section of a furnacefem-y bodying one form of the invention, with some of the associated parts added. `Figure`2 is a plan view of the apparatus disclosed in Fignielting furnace shown in Figure 1. Figure 4 is a partial verticalv section of a slightlymodified melting furnace employedrwith dif-- ferent subsequent treatment of themeltedv material. Figures and 6 are sections on the lines 5-5 and 6 6 respectively of Fig-l ure 4. Figure 'Tis an end view of the melting furnace as seen from the-right of Figure 4.A Figure Sis adiagrammatic plan view of the melting furnace arranged for a `different method of heating. Figure'9 is a plan View of a special arrangement of a plurality of melting furnaces of the 'type shown in Figure 1. I 2

The receptacle for the material being melted, as shown in lligure-l-,comprises a casing 10 Within which there is a refractory lining 11.' Where the 'sheat in the furnace is very high, one or more insulating layers l2 may be kprovided betweenthe refractory lining' and the casing, such insulation acting both to vprevent undue waste ofheat and also to maintain the casing suiiicient-ly cool to retain its strength. f

The casing is provided withsupporting and driving rings 13 which are engaged by drivingl gears 14 on a drive `shaft 15 which is i suitablyconnected by gearing 16 to a motor 17. The rings are alsosupported upon antifriction wheels, notshown, so that-the entire v,casting may be rotatedv about its ,longitudinal axis. i i

At the left end of the melting receptacle, as shown in Figure 1, there is a feeding dei vice 18 adapted to feed the material through 55 an'opening 19 in that end ofthe melting receptacle. The right endof the melting re ceptacle is provided with an' opening 20 which isi-'placed in operative'prelation' to a-heat producing furnace 21. In the construction 'so shown this heatproducing furnace is provided with an air passage22 and a gas`pas-y sage 23, theair and gas'uniting in a Hamel `which enters the right end of the meltingV receptacle and is driven to the left end .thered5 of. Some of the products of combustion passrout aroundthe feeding device into a @chimney 24, but preferably only a minor part of the products of combustionis- 'led ofi" in this manner, sutiicient tol prevent any dead areas. at that end' of vthe furnace, the greaterv part of the products of combustion returning fasindicated by arrows 25 along the lower f Vside of the melting receptacle 4.and passing l runway 27. v

The runway 27 is Vshown as being provided with tracks 28 upon which carriages 29 may be moverieach carriage supporting'a pot 30.

downward as indicated by arrow 26 into a 75 Beneath''runway 27 there is'constructedfsuit 30 i able clieckerwork 31 through which the prod- `ucts 'of combustion may be-led from the run- WayA to `any suitable chimney, not shown', this checkerwork being utilized'in any4 suit- 'able manner forjheating the gas4 and'air en- SI5 y .tering ducts 22 and 23. Y

In the construction shown'theglass melt-,7, ing receptacle and feeding device are mount-".

ed upon a-base 32 which in turn is supported Y by wheels 33 upon a track 34 so thatI the re- 90 ceptacle and feeding device may be moved i as a whole towards or from furnace 21.

4Rising from basey 32 there is a .framework 35 supporting the vmelting receptacle yand its .9.5 drive shaft. Motor17 likewise is supportedv lupon base 3,2. t From the left end ofbase 32,

t utilize cullet for filling the pores of line 11y c 18 for movement towards and from thereceiving end of the melting receptacle.

Surrounding the dischar e end of the melting receptacle there is a angey 38 which is adapted to be'moved into close proxlmity to packing 39 mounted against the stationary ring 4() on furnace 21. Beneath the discharge: end of the melting receptacle there is a block 41 adapted to act asa spillway for guiding molten glasstftom the melting receptacle into pot 30. Under the left end of base 32, as viewed in Figure 1, there may be provided a jack 42` or other similar means which may be used for elevating that end of base 32 so as to bring the melting receptacle into proper close relation with the furnace and to form a rigid foundation for thebase while the furnace vis in actual operation, and for a further purpose which will be described later.

In Figure 4 there vis shown a slight modification in which the melting receptacle` 11 is provided in roper osition to discharge material onto t e spil way block 41 from Iwhich it iows into a plaining tank 43.

For convenience the operation of the apv paratus will now be described, it being understood that theioperation of the device disclosed in Figures V1 and 4 is the same, except in respectswhich will be pointed' outphereafter. 4

When the apparatus has been assembled as indicated in Figure 1 with the discharge end of the melting receptacle in proper relation to heating furnace 21 and the feeding device 18 in roper relation to the receiving end ofthe me ting receptacle, heat is applied to the interior of the melting receptacle. The flame passing from the upper portion of furnace 21 enters the melting receptacle as indicatedby arrows 44. It will be seen that the receptacle comprises a receiving portion 45 and a discharge portion 46, each of which is in the shape of a hollow frustum of a come, with theirbases to ether at 47. As the flame proceeds longitu inally of the receptacle, it will be readily seen that it will strike against the interior ofthe receiving portion 45, as indicated by arrow 48, more directly than a ainst the approximatelyparallel but slight diverging wall of ortion 46. This more irect impingement o the flame against the wall ,portion 45.highly heats portion 45 'of the receptacle.

In first starting the furnace it is well to and glazing the interior thereof, as is well known in the use of pots and similar glass melting receptacles. When the receptacle is prepared forreceiving the glass batch and is properly heated, batch material 49 is fed into thel receiving end of the melting receptacle. This material is melted and mixed in the receptacle in a manner which will be described in detailV later. The molten glassA is discharged in a stream 50 from the discharge end of the melting receptacle onto block 41 from which it ows downward into pot 30.

Runway 27 is extended for some distance on each side of furnace 21 as indicated in F igure 2. At one end there is provided a receiv- -ing chamber 51 divided from the main portion of the tunnel by a gate 52. A pot 53 is placed in the receiving chamber and is gradually heated up in that chamber. The pot is then moved past gate 56 to discharge position 57 from whence it may be removed to utilize the molten glass in any desired manner. A v

In Figure 4 there is indicated a melting receptacle 11 substantially the same as shown in Figure 1, but being employed to deliver glass in a somewhat different condition. In

. ber 58. This chamber may itself vconstitute a dog house or gathering chamber or dog house connected thereto, or-the glass may be removed therefrom in any suitable manner.

It is preferable to heat the melting receptacle in the manner indicated in Figure 1,

wherein the fuel is introduced into the upper Y end of the discharge end of the melting-receptacle and impinges against the wall at the t receiving end thereof and thereafter is returned to the lower portion of the discharge end, with the exception of a minor amount of the products of combustion which escape in order to prevent any stagnant areas in the receiving end. However, other methods of heating may,7 be utilizedif desired. In Figure 8 .there is indicated diagrammatically a s vstem wherein the fuel is admitted in the discharge 'end 59 of the melting receptacle 11 and is discharged from the receiving end 60,

ering the waste heat by a-regenerating system, which will be readily understood without furtherdescription.` The fuel, flame and products of combustion in such a construction lll will travel as indicated by arrows 44 in Figure 4.

-If preferred, the receptacle might be heat- A in Figure 1 has advantages which will bei' more fully detailed below, the broad aspect o f the invention is not confined to this method of heating the melting receptacle and the contents thereof. l y

The arrangement shownv 1n Figure 2 may be utilized as a singleunitfor producing'glass for various purposes, but 'where this "type of melting furnace is used in alargeffactory, a series of melting furnaces may be arranged in connection with pots, as indicated in Figure 9. *In this' figure there arevindicated plurality ofV melting receptacles 6:2, 63,'64, 65, each with a furnace 66, 67, 68, etc., respectiva ly. Adjacent melting receptacles 62- and are arranged with their discharge ends d1-l rectedin opposite directionsv and between leach such pair of'melting receptacles thereV are aV pair of tunnels forpots, there being a y tunnel 69, 70, 71, etc., one Vfor each melting receptacle. The pots in each-tunnelmaybe manipulated as discussedin connection rwith Figure 2, but it is obvious that only one door tothe outside is necessary at each end of each air of tunnels, as the same door may be utilized for removing a filled pot and introducing an .empty pot if desired, therebeingv al suitable transfertruck for conveying the pot carrier from one tunnel to the other. `Th1s constitutes a compact arrangement 1n which pots may be taken filledfrom and returned` empty.r to the same places.

The meltingaction'will now be described in greater detail. As indicated above, the sloping wall of portion of the. melting receptacle becomes highly heated. Preferably material 49'isfed 'into the'receptacle in a'comparativelyfthin, broad stream, so `as to be exposed to the heat while falling ontoV the lower side of the receptacle. Whatever thev form of the stream, however, it `immediately falls upon the slopingwall of portion 45 and becomes highly heatedfby tl'1z`rtwall.l

The more easily fusible portion of the batch melts promptly upon being exposed to the. `i

heat Within the receptacle, andsurrounds the lessfusible particles mixed therewith. 'While theheating effect within the receptacle may be modified by proper control of the flames,

there is a tendency for the Vhottest flames and products-of combustionl to rise to the upper wall, so that ordinarily that-is the most highapplied throughout the interior of the refceptacledirectly to the batch..`

The coating on the upper wall'of portion 45 tends, as indicatedat 72,3 to flow' towards the entrance end of the' receptacle, some reach` ing block 73, falling onto-the upper side 79 of the feed spout, and Vflowing in a stream down the inner-end 7 6 of the spoutat a point a spaced inward from the fresh batch'stream 49.

The outward flare ofthe opening in block 7 3 aids in keeping the` molten material fromVVV flowing out of that opening. l n

The part of the batch not melted'upon first entrance intothe" furnace is rolled and tumbled along the bottom rof the receptacle -in VContact with the heated surface of the' melted coating, referred to above, and fisY mixed with the coating and melted thereby. As normally operated, there is normally a comparatively free zone77 adjacent thefeeding spout, the' unmolten portion of the batch moving forward into azone 78, whereit is similar towetsand Ilortionsf of this 1naterial carried up by the ascending wall of the receptacle, drop back in chunkfs79,as 'indi-` cated in Figure 5'. As'the material'is mixed and heated and moved forward', and is melt-l ed more andv more, it" `beeornes first stiflly plastic and then more Vand more liquid. In the plastic stage'a considerable quantity ,ad-V heres to the ascending wall andstrings down in gobs and sheets as indicated at'80.

The material in the` bottom of the` re'cep tacle tends to 1nove--by gravity fromy opposite sides vtowards plane 47.4 As Amaterial 'carried up bythe ascending wall,the direction in which-gravity tends tomoveit gradually changes `until,-when the level of' the axisof .the receptacle is reached, it r`flows downward in a plane parallel with planey 47. As it con! tinues tojascendQ-"it'turnsrnore and 'more away from'plane 47, until along the top of, the furnace'it'owsdirectly away from that plane. During the'descent of the' wall, the

change in direction continues untibwhenthe f bottom is reached itis towards plane 47 vonce 1 more. Thus during a 'rotation ofthe receptacle -the gravity movement of any portion U of glass adhered tothe -wall outside ofl 47 changesdirectionthrough 360. Considering a portion of ythe "receptacle" where there is considerable depth of material, as shown in Figure 5,it willbeapparent that.

plane wall, while the upper side 82 rolls orl flows downward, according to its consistencyv or` viscosity. Thus the'ma'terial continually rolls over' itself in? a wave 83 alongffthebottom of the receptacle. n

The speed at which the material is moved by theascending wall varies with'the dia-4 l ameter of the receptacleand is greatest along 'plane 47 and lessens at' ea-ch'side thereof. `As

a combined result of the changing direction terialV just `described and the varyingactionvdue to the changing diameter and direction,

of the wall produced by the double frustumal o lformation of the interior surface ofthe drum, a very thorough and constant mixing is effected, varying from rolling kneading, vpulling or stirring in accordance with the condition of the material. The sand or batch' ico i of the adherent coating, due to grayity,',and 1 y i viscosity and progressiveA action `of thev ina-vf mixture alongtliisllline a so." Due to heating and the mixing operation in both the central part of the drum and the part extending to near the outlet ofthe drum, gaseous materials produced the reactions of the ingradients form-:gaifoam in the more viscous glass. The foam ceases to rotatevertically and floats on thesiirface of the li 'uidmaterial and is discharged over the e ge of the diiim. The continuous .formation '.of. the

' foam. causes movement of the foam by'. dis-v V placement as .the-foam is produced. .i The 20 more viscous glass in the form of foamthus the drum.l The foamy character. of` Vthe vis cous glass immediately disappears as it passes over the `lipof tliedrum by reason-of its i distension'dueto its elongated movement and owest'poiintv in the rotating drum and inoves y voutward .towards the'. outlet 4 of ath dru displacement as it is fornied;.r 2.1...- Ihe continuous mixjing' l action,

i uicklydistribiiting the besides jt e mass,p insures uniform'v composition, and also allows the escaipe of. gases.. The interior :'30

of the receptacle eing lined withl molten a eat is directly to' the batchmateriah'not to walls of a receptacle. 'The walls of the usual -glass tank areV corroded chiefly adjacent the upper surface of the glass. There is no corresponding ine in the melting receptacle of this inventiomzjy: i

Whenglass batch is melted ina pot, heat ustppenetrate, chiefly by conduction, from thereof- In-'the usual glass melting tank,

ka'tonejend of thel tank. Lumps of the un- ."liiolten batch are formed,.these vlumps being coated with the previously molten glass; but

55 and various other factors affected by the duvent the mixing action described above.

yaction.v moves readily over the edge ofthe outletof the heat and is discharged as a viscous liquid l. from the drum." Upon discontinuance of supply of batch materials to the'drum the drum" 'awill.q'ii'i 't ;e entirely empty itself bythe lconf version'3 of the more -viscous -material .finto 1 'foain:whicli`.does not adhere to the interior "surfacefofgtliedrum but locates itselfatl'tlie,g

applied heat hrough vportions of the batch, vthe application `of hepot walls through the batch to the center batchis' dumped onto previously molten glass j the heat penetrates slowly to the middle of `many ways. Not onlythe total heat, but the relative application .of heat to 'different zones may be varied by modification of the pressure i and composition of the fuel introduced. The 75 rate of feed and the speed ofrotation of the receptacle ma also vary. to regulate the meltingand mixing action. ,Rotation should' lbe suilicientlyrapid to insure maintaining a coatin yover the-interior ofthe melting re- 86 ceptac e, andnot so rapid aste hold the material in place by centrifugal force and reariation within these limits .varies the mixing By controlling thelpapplication of `flame,

1 the .rate of rotation-and the rate of. feed, the operation ma be suited to any particulark purpose, yand Y y inspection or sampling, the condition in each successive zone can be as-r certained andany undesired action remedied vwithout waiting'for the results in the final fp'roduct.'v

i Ordinarily the of Vthe receptacle is maintained substantiallyhorizontal, vbut it by other suita lemeans. vDrops, gobs or waves of material dependingfrom the upper .-wall move away from plane 47 morerapidly than a substantiallyeven layer on the under wall flows towards plane 47 As a result, the moltenmaterialwithin the receptacle, and in excess of a coatin of a thickness to adhere to the upper wa l without marked distortion into gobs, etc., tends to flow to the@105 ends. When feedingv of kiresh batchis stopped, the material withinthe receptacle continues to ilow out until practically all of the mass is discharged.V 'A more rapid discharge maybe secured by. raising the en- 110 trance end ofthe receptacle. Atany time, the passage vof material through the recep-v tacle can be hastened by raising its entrance end, other things remaining equal. 1

In these yvarious ways the condition which the glass-leaves the receptacle can be governed to suit requirements.y

In Fig. 4 the Lglass isshown as being delivered into a comparatively large defining chamber in which the plainingis completed 1 20 and which may act as the usual refining chamber in atanlr furnace.` l

While there is indicated on vthe. drawings an arrangement whereby the pots are passed l through av plaining zone after being filled, it 125 will be readily understood that for some purposes the glass may be utilized with comparatively little plaining after being received in the pot, especially if the melting receptacle is properly manipulated to deliver the glass 13.9

95 7 vmay be tilted b manipulation of jack 42, or

in 115v inthe desired condition. 'Furthermorethe 5 to provide the plainingtunnel for the pots in connection with "the :melting 5 receptacle.

A Whilethe melt-in of the material in a rcceptacle 'such'as Y. escribed maykbe varied' quite materially according to the""'nature of lass being melted and the conditions ivvhic it is Vdesired to obtain, it will appear from fwhat* has been said above that the melting action is accomplished guita romptly. For example, it has been oun that in a furnace of the type described, a glass batch suitable for formlng plate glass may be melted and reduced `Within one hour to a condition which would correspond to about seven to nine hours in a melting pot.

where-directcontact of the flames and products of combustion is undesirable, means may be employed for heating the outside of the rece taele. Such application of heat is more detrimental to the receptacle and less etlicient than the preferred method, but is more etlicient than the usual form of mulile pot, and the advantages of the mixing action are retained. "-While the continuous operation described above is preferred, the apparatus may be operated by the intermittent method Where desired, and in any case the discharge 'maybeeifected in a continuous stream, in gobs, or Vin any other manner suitable to the circumstance.

In the operation of the rotary double frustumal receptacle in which the lass mass is heated, the batch materials are rst mixed with the fritted glass and the mixture mixes with the semi-molten glass and the molten glass, as it increases in fluidity and viscosity, adheres to the surface of the receptacle, it being drawn from the lower stratum of the Glass mass and delivered from the delivery` 45' rustum, progressively. When feeding of 2 batch materials cease, continued heating and rotation of the receptacle will cause practical- 'ly all of the mass to bev completely dis-V charged. l What is claimed is:

1. The method of melting glass which consists in progressively feeding batch materials to a heated mass of glass, rotating the mixture in a vertical plane and also in a horizontal plane and progressively separa-ting'aiid removing the molten glaSsfroni'the mixture.

2. T he method of progressively melting glass which consists in progressively feeding batch materials into previously heated fritted glass mass and rotating the glass and batch material mixture both vertically and horizontally, and progressively separating and removing the molten glass from the mixture.

The method of heating glass which consists in progressively feeding batch material For optical glass and other materials into a previously heated glass-masscontinuously rotating the glass mass' and batchmaterial mixture ina vertical plane and"l also in a horizontal plane and progressively separatingand removing the glass. mass from the horizo'iitally rotating masses the viscosity of and removing and discontinuing rotation ofV molten glass of predetermined and highest viscosity from the glassof; lower viscosity and returning molten glass of lower `viscosity towards the rotating semi-fused glass -mass and away fromthe delivery point. 4

5. The method of progressively melting glass `which consists in progressively feeding batch `materials into previously heated fritted glass mass and rotating the glass and batch material mixture both horizontally and vertically, and progressively forming a foam `from the molten glass and continuously removing the moltenfoamy glass from the mixture. o c v y y. y

G. The method ofheating glass which consists in progressively feeding batch material into a previously heated glass mass, continuously rotating'the glass mass and batch material mixture in a vertical plane and also in a'horizontal planerand forming a foam and continuously removing the glass of the foam from the glass mass by the` displacement of the previously formed foam as the foam is created. n Y l 7. The method of heating glass which consists in progressively feed-ing'batch material into a previously heated glass mass,` continuy ously rotating the glass mass and batch Amaterial mixture in both vertical and horizon-- tal planes and progressively forming a foam from the glass as its viscosity increases and continuously removing thel .morev viscous glass. '1"' v 8. The method of heating glass which consists in progressively feeding batch .materials into a previ'ousl heated glass mass, continuously rotating t e glass4 mass vand glass material mixture in a vvertical plane and also in a horizontal plane and progressively forming a foam that ceases to vertically rotate and continuously discharging the previouslyv formed foam by the foam as it is created.

9. The method of melting glass which consists in progressively feeding glass batch'ma- .A-"ltei'ials into aheated fused glass mass, producing rotation ot' the glass mass and batch material mixturi` in a vertical plane.l progressively separating and iciiioving portions o't the glass inass as it reaches a predetermined viscosity from the rotation, and moving progressively the molten glass-material towards thel delivery point of tlie glass as the viscosr ity of the glass increases and continuously preventing movement of the molten glass to the delivery point until .its viscosity increases viscous glass.

`10. The method of melting glass which` consists in progressively feeding glass hatch materials into a heated glass mass and producing rotation of the glass mass and hatch material mixture in vertical planes and progressively moving the port-ions ot the. glass hatch material away from the central zone of the glassmass'and hatch material mixture towards a glass discharging point Where the glass is removed 'from the melting glass 'as the viscosity of the glass increases and moving the glass mass of lower viscosity away from the said discharging point and torming a oain on the surface ot the lower viscous glassand continuously discharging the glass of the foam from the glass discharging point.

11. The method of progressively melting glasswhich consists in'continuously feeding glass materials into a previously' heated glass mass continuously heating the' glass mass and batch materials andthcreby continually changing the adherability and viscosity ot the glass mass, continuously rotating the glass mass batch material both vertically and horizontally and lprogressively separating and removing the glass mass from the mixbatch materials bothvertically and horzontally forming a foam from the more viscous glass and discharging the glass of the foam as the foam is formed.

13. A method of heating glass which consists in'feeding glass batch materials into a heated fused glass mass, continuously heating and rolling the hatch materials into the fused glass mass to mix the batch materials of the fused mass and thereby varying the adherability and viscosity of the glass, carrying portions of the more adherable glass forward and allowiigfit to fall into lower portions of the glass mass, and forming foam In testimony whereof I have hereunto signed my name to this specification.

FRANCIS J. BULASK. 

